Dynamic fluctuations of protein-carbohydrate interactions promote aggregation
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Voynov-2009-Dynamic fluctuations.pdf
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Author(s)
Voynov, Vladimir
Chennamsetty, Naresh
Kayser, Veysel
Helk, Bernhard
Forrer, Kurt
Zhang, Heidi
Fritsch, Cornelius
Heine, Holger
Trout, Bernhardt L.
Date Issued
December 2009
Journal
PLoS ONE
Publisher
Public Library of Science
Citation
Voynov, Vladimir, et al., “Dynamic fluctuations of protein-carbohydrate interactions promote protein aggregation.” PLoS ONE 4, 12 (Dec. 2009): no. e8425 doi 10.1371/journal.pone.0008425 ©2009
Version
Final published version
Abstract
Protein-carbohydrate interactions are important for glycoprotein structure and function. Antibodies of the IgG class, with increasing significance as therapeutics, are glycosylated at a conserved site in the constant Fc region. We hypothesized that disruption of protein-carbohydrate interactions in the glycosylated domain of antibodies leads to the exposure of aggregation-prone motifs. Aggregation is one of the main problems in protein-based therapeutics because of immunogenicity concerns and decreased efficacy. To explore the significance of intramolecular interactions between aromatic amino acids and carbohydrates in the IgG glycosylated domain, we utilized computer simulations, fluorescence analysis, and site-directed mutagenesis. We find that the surface exposure of one aromatic amino acid increases due to dynamic fluctuations. Moreover, protein-carbohydrate interactions decrease upon stress, while protein-protein and carbohydrate-carbohydrate interactions increase. Substitution of the carbohydrate-interacting aromatic amino acids with non-aromatic residues leads to a significantly lower stability than wild type, and to compromised binding to Fc receptors. Our results support a mechanism for antibody aggregation via decreased protein-carbohydrate interactions, leading to the exposure of aggregation-prone regions, and to aggregation.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
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DOI of Published Version
http://dx.doi.org/10.1371/journal.pone.0008425
